Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchiv

Natesan, Usha

Rajagopalan, V.

Venkatesan, G.

English

Hydraulic Engineering Repository

Conference Paper, Published VersionRajagopalan, V.; Natesan, Usha; Venkatesan, G.The Pattern of Seasonal Sediment Transport MechanismsAround Arichaimunai by Sediment Trend Matrix (STM)Zur Verfügung gestellt in Kooperation mit/Provided in Cooperation with:Kuratorium für Forschung im Küsteningenieurwesen (KFKI)Verfügbar unter/Available at: https://hdl.handle.net/20.500.11970/109928Vorgeschlagene Zitierweise/Suggested citation:Rajagopalan, V.; Natesan, Usha; Venkatesan, G. (2010): The Pattern of Seasonal SedimentTransport Mechanisms Around Arichaimunai by Sediment Trend Matrix (STM). In: Sundar,V.; Srinivasan, K.; Murali, K.; Sudheer, K.P. (Hg.): ICHE 2010. Proceedings of the 9thInternational Conference on Hydro-Science & Engineering, August 2-5, 2010, Chennai, India.Chennai: Indian Institute of Technology Madras.Standardnutzungsbedingungen/Terms of Use:Die Dokumente in HENRY stehen unter der Creative Commons Lizenz CC BY 4.0, sofern keine abweichendenNutzungsbedingungen getroffen wurden. Damit ist sowohl die kommerzielle Nutzung als auch das Teilen, dieWeiterbearbeitung und Speicherung erlaubt. Das Verwenden und das Bearbeiten stehen unter der Bedingung derNamensnennung. Im Einzelfall kann eine restriktivere Lizenz gelten; dann gelten abweichend von den obigenNutzungsbedingungen die in der dort genannten Lizenz gewährten Nutzungsrechte.Documents in HENRY are made available under the Creative Commons License CC BY 4.0, if no other license isapplicable. Under CC BY 4.0 commercial use and sharing, remixing, transforming, and building upon the materialof the work is permitted. In some cases a different, more restrictive license may apply; if applicable the terms ofthe restrictive license will be binding.Proceedings of ICHE2010, IIT Madras, Aug 2-5,2010      The pattern of seasonal sediment transport mechanisms around arichaimunai by sediment trend matrix (stm)                     317    THE PATTERN OF SEASONAL SEDIMENT TRANSPORT MECHANISMS AROUND ARICHAIMUNAI BY SEDIMENT TREND MATRIX (STM)  Rajagopalan V.1, Usha Natesan2 and G. Venkatesan3                                         Abstract:  The coast is a zone of intense energy input. This energy, transported by waves arrives at the coast which set the processes of sediment transport in motion and driven by forces such as waves, tides and wind that causes morphological change.   Sedimentary coastlines have an attraction to many human beings. The study on the pattern of seasonal sediment transport mechanism around Arichamunai will provide a management tool for rapid assessment of natural hazard risk potential and it is important for such activities as economics, development, tourisms, planning research, science and education   etc. This   study   was   analyzed   using   toposheets   and   beach   samples characteristics. From beach samples characteristics, Grain size analysis followed by the computation   of   Sediment   Trend   Matrix   (STM)   helps   to   understand   the   sediment movement from various stations and points out the sediment sources and sinks around Arichamunai   and   also   showed   that   predominant   direction   of   the   sediment   transport during the premonsoon and monsoon is from south to north and reversed during post monsoon season.  Keywords: coast; sediment; grain size; sources and sinks.   INTRODUCTION  The coast is a zone of intense energy input.   This energy, transported by waves arrives at the coast which set the processes of sediment transport in motion and driven by forces such as waves, tides and wind that causes morphological change. Sedimentary coastlines have an attraction to many human beings. (Benedet et al., 2004). For many of them it is a place to relax, for others it is a way to earn a living either on the dry part or from the regions offshore, consequently coast lines have become densely populated areas.  These reasons make the presence and quality of a sandy coastline a valuable asset.  ______________________________________________________________________________ 1 Lecturer, Department of Civil Engineering, Anna University Tiruchirappalli, Tiruchirappalli 620 024, India, Email: rarohit@yahoo.com 2 Professor, Centre for Environmental Studies, Anna University, Chennai-600 025, India,  Email: u_natesan@yahoo.com 3 Lecturer, Department of Civil Engineering, Anna University Tiruchirappalli, Tiruchirappalli 620 024, India, Email: gvenkat1972@gmail.com  Proceedings of ninth International Conference on Hydro-Science and Engineering (ICHE 2010), IIT Madras, Chennai, India. 2 - 5  August 2010   Proceedings of ICHE2010, IIT Madras, Aug 2-5,2010      The pattern of seasonal sediment transport mechanisms around arichaimunai by sediment trend matrix (stm)                     318Coastal sediment management is an issue that has attracted the attention of coastal manager, engineers, planners and the like. (Chang et al., 2001).The study on the pattern of seasonal sediment transport mechanisms around Arichaimunai will provide a management tool for rapid assessment of natural hazard risk potential and it is important for such activities as economics, development, tourisms, planning research, science and education etc. Around 6 km coastal stretch of  Dhanushkodi – 3 km on either side of Arichamunai,  lying between 9° 11’ N - 9° 9’ N latitude and 79° 26’ E - 79° 24’ E longitudes was considered as study area. This study is very much essential because this area is one of the vulnerable sites affected by cyclone in 1964, which cause great damage due to flooding and siltation (Nayak S 2002).   MATERIALS AND METHODS  The Base map of Dhanushkodi was prepared from Survey of India toposheets of 1977 in 1:25000 by tracing the shoreline and then digitized using ARCGIS (Ramaswamy et al., 2004). Beach samples were collected from seven locations around Archamunai, Dhanushkodi, during different seasons - premonsoon, monsoon, postmonsoon. The sampling locations were identified with a hand held GPS and placed in the base map is shown in Figure 1. At each sampling location about 150-200 g of unconsolidated wet sand was collected with a scoop from topmost layers approximately 3~5 mm thick. The samples were packed in polythene covers and grain size analysis was carried out. In grain size analysis, the moisture content from collected samples was removed by oven drying.  Then these dried samples were weighed for finding initial weight and then sieve process had been carried out in a single stack through 10 sieves for 20 minutes using Ro-Tap sieve shaker. The sand retained on each sieve was carefully removed and again weighted which was converted into cumulative weight percentage retained. (Falco et al., 2003).   The textural parameters of grain size are dependent upon the environment in which is located such as deserts, rivers, beaches, etc (Weber et al. 2003).  Further, within a given environment, these characteristics differ spatially with response to various sediment transport process. Statistical measures such as mean, sorting and skewness help to differentiate the distribution of sand genetically meaningful. These statistical measures of the grain size parameters as proposed by Folk and Ward (1957) were adopted in the present study. The formulae used to calculate the statistical parameters and their range are given in Table 1 and Table 2 respectively.  Proceedings of ICHE2010, IIT Madras, Aug 2-5,2010      The pattern of seasonal sediment transport mechanisms around arichaimunai by sediment trend matrix (stm)                     319 Fig.1. Base map with sampling stations  Table 1.  Statistical for Size - Frequency Distribution  Sl.No. Name of the  Statistical Parameter  Formulation 1 Mean 3845016  Mz 2 Standard Deviation or Sorting 6.6459516841  3 Skewness )(22)(225955095516845084161 Sk   Proceedings of ICHE2010, IIT Madras, Aug 2-5,2010      The pattern of seasonal sediment transport mechanisms around arichaimunai by sediment trend matrix (stm)                     320Table 2.  Range of Statistical Parameters A) Classification of Grain Size Based on Mean Sl.No. Mean Mz () 1 Pebbles -3 to -2  2      Gravel -2 to -1  3      Very Coarse sand -1 to 0  4 Coarse sand 0 to +1  5 Medium sand +1 to +2  6 Fine sand +2 to +3  7 Very fine sand +3 to +4  8 Coarse silt +4 to +5    B) Classification of Grain Size Based on Sorting and  Sl. No. Sorting (1) Skewness (SkI) 1 Very well sorted < 0.35 Very fine skewed +0.3 to 1.0 2 Well sorted 0.35 – 0.50 Fine skewed +0.1 to 0.3 3 Moderately well sorted 0.50 – 0.70 Symmetrical +0.1 to –0.1 4 Moderately sorted 0.70 – 1.00 Coarse skewed -0.1 to –0.3 5 Poorly sorted 1.00 – 2.00 Very coarse skewed -0.3 to –1.0 6 Very poorly sorted 2.00 – 4.00  7  Extremely poorly  sorted > 4.00  GRADISTAT, a statistical program developed by Blott (2000), was used to calculate the mean, sorting, skewness from the grain size fractions. A tool was developed using C language to derive the STM from statistical parameters. This tool compares the statistical parameters between two stations to derive the STM. The following conditions were used in the comparison:    Proceedings of ICHE2010, IIT Madras, Aug 2-5,2010      The pattern of seasonal sediment transport mechanisms around arichaimunai by sediment trend matrix (stm)                     321IF,        Mean[1] = Mean[2]    S Same       Mean[1] < Mean[2]    F Fine  Mean[1] > Mean[2]    C Coarse       Sorting[1] = Sorting[2]    S Same     Sorting[1] < Sorting[2]    P Poor      Sorting[1] > Sorting[2]    B Better        Skewness[1] =  Skewness[2]  S Same        Skewness[1] <  Skewness[2]  + Positively skewed        Skewness[1] >  Skewness[2]       -    Negatively skewed The procedure adopted in the STM analysis using statistical parameters is explained along with a typical example – location No.1 as follows: i. The cumulative percentage finer from sieve analysis were calculated. Typical sieve analysis data for location No.1 for pre-monsoon period is given in Table 3. ii. Cumulative percentage finer was plotted on log - probability scale. iii. To  - values corresponding to the percentage of exceedance were taken from log – probability plots and statistical parameters were calculated using the formulae given by Folk and Ward (1957) and for location No.1, MZ =1.986, σ =0.498 and Sk = 0.203  iv. In the similar way, statistical parameters were determined for all the samples for different periods and finally STM was drawn. v. The results of the STM were represented in the pictorial form called   Sediment Transport Path (STP) (Roux et al., 2002).   Proceedings of ICHE2010, IIT Madras, Aug 2-5,2010      The pattern of seasonal sediment transport mechanisms around arichaimunai by sediment trend matrix (stm)                     322Table 3.  Sieve Analysis – Sample 1 ASTM Mesh No. Aperture  in  mm Equivalent diameter (Φ) mm Weight (g) Weight % retained Cumulative % retained 18 1.000 0.00 0.1 0.04 0.04 25 0.707 0.50 00 00 0.04 35 0.500 1.00 2.6 1.04 1.08 45 0.354 1.50 26.3 10.52 11.6 60 0.250 2.00 119.4 47.76 59.36 80 0.177 2.50 58.2 23.28 82.64 120 0.125 3.00 42.0 16.8 99.44 170 0.088 3.50 1.2 0.48 99.92 230 0.062 4.00 0.2 0.08 100.00 375 0.044 4.50 0 0 100.00 Pan _ _ 0 0 100.00  RESULTS AND DISCUSSION The Statistical parameters are computed along the coast of Dhanushkodi for premonsoon, monsoon and postmonsoon seasons. The Sample Statistical parameters for premonsoon season along with inferences is given in Table 5. The statistical parameters were compared by considering each location as a source and other locations as possible deposits and then tabulated. This is called Sediment Trend Matrix. The sediment movement trends were drawn based on the results of STM. If the deposit is finer, better sorted and more negatively skewed it shows case I trend (Total deposition). If the deposit is finer or coarse but better sorted and positively skewed it shows case III (Partially deposition in transport) McLaren (1981). The Sample STM of the premonsoon is  given in Tables 4. Then major source and sink locations for each period are observed from the trend maps, the sample trend map is in Figure 2, and tabulated in Table 6.     Proceedings of ICHE2010, IIT Madras, Aug 2-5,2010      The pattern of seasonal sediment transport mechanisms around arichaimunai by sediment trend matrix (stm)                     323  Table 4. Sediment Trend Matrix - Premonsoon (19.08.2005) Location Sediment Source Parameter Inferences P1 P2 P3 P4 P5 P6 P7  S E D I M E N T  D E P O S I T      P1  F F C F F F Mean P1  P2, P4 P B P B P P Sorting - + - - + + Skewness P2 C  F C F F F Mean  P2  P4  B B P B P P Sorting + + - - + + Skewness P3 C C  C F C F Mean P3  P1, P2, P4, P6, P7 P P P P P P Sorting - - - + - - Skewness P4 F F F  F F F Mean  ---------  B B B B P P Sorting + + + + + + Skewness P5 C C F C  F F Mean P5  P1, P2, P4 P P P P P P Sorting + + + - + + Skewness P6 C C F C C  F Mean  --------------  B B B B B B Sorting - -   + - - + Skewness P7 C C C C C C  Mean P7  P6 B B B B B P Sorting - - + - - - Skewness      Proceedings of ICHE2010, IIT Madras, Aug 2-5,2010      The pattern of seasonal sediment transport mechanisms around arichaimunai by sediment trend matrix (stm)                     324Table 5. Statistical Parameters Location Premonsoon (19.08.2005) Mean (mm) Sorting (mm) Skewness (mm) P1 1.986 0.498 0.203 P2 1.854 0.430 0.211 P3 1.537 0.542 -0.071 P4 2.054 0.426 0.273 P5 1.844 0.610 0.227 P6 1.566 0.367 -0.032 P7 1.402 0.420 -0.039 Inference Medium sand Well Sorted Fine Skewed to Symmetrical   7654321Palk BayGulf of MannarDhanushkodiCase 2Case 1LegendProbabledirction of Sediment TransportDeposit P2,P4Source P3,P5 Fig.2. Sediment Trend Paths – Premonsoon (19.08.2005)    Proceedings of ICHE2010, IIT Madras, Aug 2-5,2010      The pattern of seasonal sediment transport mechanisms around arichaimunai by sediment trend matrix (stm)                     325Table 6. Source and Sink locations Sl.No Period Major Source Major Sink 1 August 2005 P3, P5 P2, P4 2 October 2005 P3 P1, P2 3 December 2005 P2, P3, P4, P1, P5, P6, P7 4 February 2006 P3, P7 P2, P5, P6  The result of this trend show that predominant direction of the sediment transport during the premonsoon and monsoon (16.10.2005) is from south to north and reversed during monsoon (25.12.2005) and postmonsoon seasons. From the Table 6, P2 (along Palk Bay) and P5, P6 are observed to be major sink locations and P3 (along Palk Bay) is to be major source for sediment.   CONCLUSIONS Sediment dynamics of the area was analyzed from the beach samples collected at seven stations along the shoreline during different seasons. Grain size analysis was done and statistical parameters such as Mean, Sorting and Skewness of the grain size were computed. Sediment Trend Analysis was done using McLaren (1981) one dimensional model. Sediment Trend Matrix was prepared to determine the probable source and sink for the sediment. Sediment transport paths for the premonsoon, monsoon and postmonsoon seasons were then determined with the help of STM. The direction of sediment transport in premonsoon and monsoon period is reversed in comparison with the postmonsoon. The sediment movement trends show that P2 (along Palk Bay) and P5, P6 (along Gulf of Mannar) are the major sink locations and P3 (near Arichamunai) is the major source for sediment.  REFERENCES  Benedet L., Finkl C.W., Klein A.H.F., 2004. Morphdynamic classification of beaches on the Atlantic coast of Florida; Geographical variability of beach types, beach safety and costal Proceedings of ICHE2010, IIT Madras, Aug 2-5,2010      The pattern of seasonal sediment transport mechanisms around arichaimunai by sediment trend matrix (stm)                     326hazards. J. Coast. Res. 39(8), 1-8.  Chang Y.H., Scrimshaw M.D., Lester J.N., 2001. A revised grain size trend analysis program to define sediment transport pathways. Computers and Geosci. 27,109-114.  Falco G.D., Mohinaroli E., Baroli M., Bellacicco S., 2003. Grain size and compositional trends of sediments from Posidonia oceanic a meadows to beach shore, Sardinia western Mediterranean. East Coast and Shelf Sci. 58, 299-309.  Folk R.L., Ward W.C., 1957. Brazos river bar: A Study in the significance of grain size parameters. Journal of Sediment. Petrol. 27(1), 3-26.  Mclaren P., 1981. An interpretation of trends in grain size measures. Journal ofsediment. Petrol. 51(2), 611-624.   Nayak S., 2002. Coastal Zone Management. Indian Society of Geomatics Newsletter. 9, 29-30.  Rodriguez H.N. and Mehta A.J. (2000), ‘Longshore transport of fine grained sediment’, Coast Shelf Res., Vol.20, pp.1419-1432.  Roux J.P., O’Brien R.D. and Listernas M. (2002), ‘Short note: analysis of sediment transport paths using grain size parameters’, Computers and Geosci., Vol.28, pp.717-721.  Sanjeev R., Subraminam V., 2003. Landuse / Landcover changes in Asthamudi Wetland region of Kerala – A study using Remote Sensing and GIS. Journal of Geological Society of India. 61, 573-580.  Weber M.E., Wiedicke-Honbach M., Kudrass H.R., Erlenkeuser H., 2003.Bengal fan sediment transport activity and response to climate forcing inferred from sediment physical properties. Sediment.Geol., 30,361-381.  

The Pattern of Seasonal Sediment Transport Mechanisms Around Arichaimunai by Sediment Trend Matrix (STM)

http://henry.baw.de/bitstream/20.500.11970/109928/1/033_ICHE_2010.pdf

The Pattern of Seasonal Sediment Transport Mechanisms Around Arichaimunai by Sediment Trend Matrix (STM)

Abstract

Similar works

Full text

Available Versions

Hydraulic Engineering Repository